Process of recovering borax from solutions containing sodium borates



UNlTED STATES PATENT OFFICE.

CARL SUNDSTROM, 0F SYRACUSE, NIH/V YORK, ASSIGN'OR TO THE SOLVAY PROCESS COMPANY, OF SOLVAY, NEYY YORK, A CORPORATION OF NEW YORK.

EROCESS O RECQVERING BDRAX FROM SOLUTIONS CONTAINING SODIUM BORATES.-

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No Drawing.

To all whom it may concern:

I Be it known that I, CARL SUNosrRoM, a citizen of the United States, residing in Syracuse, in the county of Onondaga and State of New York, have invented a new and Improved Process of Recovering Borax from Solutions Containing Sodium Borates, of which the following is a specification.

In the treatment of natural alkaline deposits, such as the waters of Searles lake in California, for the recovery of their con tents of value, it is desirable to keep the sodium borate content of the liquor in the form of soluble metaborate until the precipitation of as much as possible of the potassium chlorid .content is effected and then to convert the metaborate into the rela-' this conversion according.to an equation of the type 4NaBO +CO =Na B 0,+Na UO;,

entering into combination and is thus wasted.

.l have found, however, that if a reagent is introduced into the solution whereby CO is set free or formed within the solution itself, the CO, is brought into intimate contact with the metaborate throughout the mass and in a nascent or quasi nascent state, and the reaction is effected neatly and eiliciently and without waste. This is made possible by the fact that sodium carbonate is always present in such a solution in such quantity that sullicient CO can always be set free therefrom to effect the reaction.

The addition of an acid, or of any substance containing CO setting up an acid reaction, or working in any way to release ()0 from the M 00 will keep the reaction in the above stated equation moving from left to right, or, in other words, change the metabow-ate to tetraborate. I do not wish to be Specification of Letters Patent.

content as from the SO Patented Aug. 10, 1920..

Application filed September 24, 1919. Serial No. 325,910.

understood as limiting myself to the use of any one reagent. As long as the basic equation given above is involved and the CO 1s evolved in situ, it may be used in my process.

I shall illustrate my invention by describing three applications of the use of this basic equation in recovering borax from mother liquors, or solutions containing borates, although the invention is not restricted to the use of these reagents to bring about the reaction described. I shall describe the following: I

1. The treatment with sulfur dioxid 2. The treatment with trona 3v The treatment with aluminum sulfate Sulfur diomid treatment.

Sulfur dioxid gas is conducted into the mother liquor slowly and with frequent agitation. The absorption of the gas by the mother liquor at room temperature is prac tically 100 per cent. eflicient. Temperature as high as 50 C. appear to have no retarding effect on this absorption. The equation involved in this action is:

Treat-meat with tram.

Sodium bicarbonate will convert metaborate into tetraborate according to the reaction T'rona, as naturally deposited, is one.

source of bicarbonate. The pure mineral has the compos1tion: Na CO,,NaHCO BH O, (2., 37 per cent. NaHCO The mother liquor is treated with trona at 24 U. for 24 hours, and the same reduction of borax treatment is obtained.

carbon dioxid is caused to be set free within the solution so as to convert the metaborate into sodium tetraborate.

3. The process of removing sodium metai borate from solution which consists in introducing into the solution an acid reagent whereby carbon dioxid is caused to be set free Within the solution so as to convert the Treatment with aluminum sulfate.

If sodium metaborate and sodium. carbonate are treated with aluminum sulfate, the following reaction takes place, probably proceeding in two stages:

As pure aluminum sulfate is too expensive to be practical 'commerclally, I prefer'to use some crude aluminum sulfate of the comcipitating the tetraborate. to -14. The process of removing sodium metabora'te from solution which consists in breaking up a constituent of the solution so as to set free carbon dioxid within the posmon: r tating the tetraborate. AI,(SO 38.60% he process otremoving sodium meta- 5 Moisture, 24.50 1? f O H solutlon which cons sts in- Insolubles, 27.90 eakmg up sodium carbonate contained in so the solution so as to set free within the solution carbon dioxid whereby the metaborate is "converted into sodium tetraborate and precipitating the tetraborate.

he process of removing sodium Inetaborate from solution which consists in breaking up sodium carbonate contained in the solution so as to set free within the solution carbon dioxid, causing the carbon dioxid to combine with the metaborate so To eliminate the insoluble material contained in the crude sulfate I make a saturated solution of A1,,(S containing 381 g. p. l. Al (SO This solution is added to the mother liquor. This treatment also effects the 50 percent. reduction of the metaborate content in the mother liquor.

Having thus described my invention,

what I claim as new and desire to secure as to form sodium tetraborate with recon-' by Letters Patent is I stitution of the sodium carbonate and prel. The process of removing sodium metacipitating the tetraborate.

In testimony whereof I have affixed my signature, this 8th day of September,- 1919.

CARL SUNDSTROM.

solution which consists in forming carbon dioxid Within the solution so as to convert the metaborate into sodium tetraborate and precipitating the tetraborate.

borate from 2. The .process of remd ving sodium meta- Witnesses: borate from solution which consists in intro- B. L. THoMrsoN,

a reagent whereby J. DENNY.

ducing into the solution 

